1. Field of the Invention
The present invention relates to a connecting device used for connecting a high-voltage cable to a connector portion provided in a transformer. The transformer generates a high electrical voltage. The high electrical voltage thus produced is applied to electrical apparatuses, such as office or home appliances for different purposes. The connecting device according to the invention is used for sending the high electrical voltage to the electrical apparatuses. Further, the invention concerns methods of connecting such a high-voltage cable to a transformer.
2. Description of Background Information
FIG. 1 shows a known connecting technique, according to which a high-voltage cable used for sending a high electrical voltage is connected to a connector portion 3 of a transformer 1 in such electrical apparatuses. With this technique, once a connector portion 3 of the transformer 1 is connected to a high-voltage cable 5 for sending a high electrical voltage, there is no need to detach them. Accordingly, the high-voltage cable 5 is stripped off of its coating, thereby yielding a conductive portion 5a, and the conductive portion 5a is soldered to the connector portion 3 of transformer 1.
The transformer 1 comprises a vertically-extending housing 7. The housing 7 contains a primary coil and a secondary coil which generate high electrical voltages as a function of the inputted variable current. The housing 7 may also contain various electronic parts such as condensers, diodes or impedance elements, connected to each coil. The housing 7 is provided with a hollow portion 7a and a base from which a connector portion 3 of the transformer 1 extends into the hollow portion 7a. The end portion of the secondary coil of transformer 1 may thus be connected to an electronic component. The latter includes an end section which may form a rod-shaped terminal portion. Accordingly, the connector portion 3 of transformer 1 may be comprised of the terminal portion of an impedance element, e.g. a capacitor in the housing 7. However, the connector portion 3 of transformer 1 may also be comprised of a lead wire extending from the electronic component.
The high-voltage cable 5 usually has a conductive portion 5a consisting of a plurality of copper wires, and a resin coating. When the high-voltage cable 5 is connected to a connector portion 3 of transformer 1, an epoxy resin or the like is filled into the hollow portion 7a, so that the connected portion between the high-voltage cable and the connector portion 3 of the transformer 1 is sealed with the resin. Thereafter, a rubber grommet 9 is fitted onto part of the circular peripheral zone of the high-voltage cable 5. The hollow portion 7a of housing 7 includes a rectangular side chamber, whose outermost face has a notch 7b vertically atop thereof. After the high-voltage cable 5 has been mounted into the housing 7, the space formed between the notch 7b and the high-voltage cable 5 is closed by the rubber grommet 9, such that the sealing resin is prevented from overflowing.
When the transformer 1 generates a high electrical voltage, it also generates noise through the high-voltage cable 5, and hence a countermeasure for reducing noise becomes necessary. To this end, either a magnetic core is set around the cylindrical outer surface of the high-voltage cable 5, or an impedance element is inserted in the conductive part of the high-voltage cable 5 so as to curb the noise current flowing in the high-voltage cable 5. However, these methods yield only a limited effect, and there is a need for a more efficient noise-suppressing technique.
To further improve noise-suppressing efficiency, a coiled-type, high-voltage noise-suppressing cable may be used, instead of the high-voltage cable 5. The coiled-type, high-voltage noise-suppressing cable comprises at least a core element of magnetic material, a coiled portion at least including a conductive wire for passing a high electrical voltage. The coil is helically wound around the core element, and a coating entirely covers the core element and coiled portion. Such a structure is designed to suppress noise efficiently.
The conductive wires commonly used in a coiled-type cable for preventing high-voltage noise include wires such as nickel-chromium wires. However, such conductive wires are ill suited for soldering. Accordingly, when using the above technique, the high-voltage cable 5 cannot be soldered directly to the connector portion 3 of the transformer 1.
An object of the present invention is to provide a connecting device with improved noise-suppressing capacity using a coiled-type cable for preventing high-voltage noise and which can easily connect the coiled-type, high-voltage noise-suppressing cable to a transformer, as well as to provide a method of connecting the coiled-type, high-voltage noise-suppressing cable to the transformer.
To this end, according to one aspect of the present invention, there is provided a metallic connecting device for connecting a high-voltage electrical cable to a transformer having a connector portion from which a high electrical voltage is outputted. The high-voltage electrical cable includes a coiled-type high-voltage noise-suppressing cable including at least a coiled core element containing a magnetic material and at least a conductive wire through which the high electrical voltage is passed, the conductive wire being wound around the magnetic material, and a coating covering the coiled core element.
The connecting device includes a crimping connector portion adapted for press-fitting the coiled-type high-voltage noise-suppressing cable, and a solder connector portion formed in extension of the crimping connector portion and adapted for connecting to the connector portion of the transformer by soldering.
In another aspect of the present invention, the transformer is provided with an electronic part including a rod-shaped terminal portion. The connector portion of the transformer may include the rod-shaped terminal portion, while the solder connector portion of the connecting device may be substantially in the form of a cup having a base with a through hole. The rod-shaped terminal portion is then passed through the through hole, and connected and fixed to the solder connector portion by soldering.
Alternatively, the solder connector portion of the metallic connecting device may include a substantially flat plate which is put into contact with the rod-shaped terminal portion along the length direction thereof. The rod-shaped terminal portion is then connected and fixed to the solder connector portion by soldering.
In a further alternative, the solder connector portion of the connecting device may include a pair of lips extending substantially in parallel, between which the rod-shaped terminal portion is inserted. The rod-shaped terminal portion is then connected and fixed to the solder connector portion by soldering.
When using the metallic connecting device of the invention, the coiled-type high-voltage noise-suppressing cable typically includes an end portion which is stripped of its coating so that the coiled portion is exposed. The crimping connector portion may include a first barrel portion in which the coiled portion of the coiled-type high-voltage noise-suppressing cable is press-fitted, and a second barrel portion in which the coiled-type high-voltage noise-suppressing cable is crimped from above its coating.
Advantageously, the second barrel portion includes a base wall and a detent formed on the base wall.
According to another aspect of the present invention, there is also provided a method of connecting a transformer containing a connector portion to a high-voltage electrical cable having an end portion. The method includes: a) preparing a coiled-type high-voltage noise-suppressing cable used as a high-voltage electrical cable, the coiled-type high-voltage noise-suppressing electrical cable including a coiled core element containing a magnetic material and a coiled portion, the coiled portion including a conductive wire through which a high electrical voltage is passed, the conductive wire being wound around the magnetic material, and a coating covering the coiled core element.
The method also includes: b) stripping the end portion of the coating so that the coiled portion is exposed, and c) preparing a connecting device. The metallic connecting device includes a crimping connector portion adapted for press-fitting the coiled-type high-voltage noise-suppressing cable, and a solder connector portion provided in extension of the crimping connector portion and adapted for connecting the connector portion of the transformer to the end portion of coiled-type high-voltage noise-suppressing cable by soldering.
The method further includes: d) press-fitting the coiled-type high-voltage noise-suppressing cable in the crimping connector portion, while connecting and fixing the end portion of the coiled-type high-voltage noise-suppressing cable to the connector portion of the transformer by soldering at the solder connector portion,
whereby the transformer is connected and fixed to the coiled-type high-voltage noise-suppressing cable via the metallic connecting device.